Title of Thesis

Characterization of Black Cumin Seed Oil and Exploring its Role as a Functional Food

Abstract

TIn the present research project, black cumin seed oil (fixed & essential) was characterized, used in cookies formulation, and tested for its nutraceutical potential against oxidative stress, diabetes and dyslipidemia through rat modeling studies. Compositional analysis revealed that fixed oil is a rich source of polyunsaturated fatty acids, tocopherols and to some extent thymoquinone, whilst essential oil was abundant in bioactive molecules like thymoquinone, p-cymene, carvacrol, α-thujene and thymol. Both oils inhibited in vitro lipid peroxidation and scavenged DPPH radicals significantly. Afterwards, fixed and essential oils were added in the cookies at varying levels to enrich the formulation. The functional ingredients of the respective oils improved the oxidative stability of the cookies with better hedonic response over control. Considering the results of characterization and product development; fixed oil @ 4% and essential oil @ 0.3% were selected for further use in efficacy study. The experimental rats modeling comprised of four segments including normal, oxidative stressed, diabetic and hypercholesterolemic Sprague Dawley rats. Initial trials were conducted in normal rats; indicated that diets prepared with fixed and essential oils hold hypoglycemic and hypocholesterolemic perspectives. Moreover, reduction in oxidative damage, improvements in antioxidant status and modulation of hepatic antioxidant enzymes were also observed in groups fed on diet containing fixed and essential oils. In oxidative stressed rats, serum MDA and conjugated dienes levels were significantly reduced by 20.58 and 51.62% in black cumin fixed and essential oils groups, respectively. Moreover, experimental diets enhanced the total antioxidant capacity and antioxidant status as compared to the control. Similarly, activities of hepatic enzyme and parameters associated with immunity were modulated significantly. Allied discrepancies like elevated cholesterol and glucose during stress were markedly reduced as a function of black cumin fixed and essential oils diets however, essential oil gave better performance and can be used as safeguard against the menace. In the third section, streptozotocin injection was used to induce diabetes mellitus in rats. There observed decrease of 4.10 and 10.23% for glucose in fixed and essential groups, respectively, as compared to 33.21% rise in control. Furthermore, insulin level decreased significantly in control group i.e. 51.72% as compared to increasing trend in fixed and essential oils groups i.e. 5.63 and 10.43%, respectively, indicated that experimental diets hold insulinotropic potential. It was noted that management of antioxidant status and lipid profile were cardinal in controlling diabetic complications. Finally, efficacy trials were conducted involving hypercholesterolemic rats. In control group, momentous increase in serum cholesterol, triglycerides and LDL levels was observed, whereas fixed and essential oils attenuated the cholesterol 10.70 & 5.44%, triglycerides 19.35 & 5.45% and LDL 15.38 & 12.79%, respectively. Improvements in antioxidant status and reduced oxidative damage were also observed. Both oils reduced the serum glucose significantly by enhancing insulin secretion. Correlation matrix indicated significant association among indices of oxidative damage, lipid profile and glucose response. From the present study, it is deduced that black cumin fixed and essential oils can be supplemented in food products for the management of these maladies.

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